On 11/26/23 11:37, Andy Smith wrote:
Hello,
On Sun, Nov 26, 2023 at 11:18:39AM +0100, Gandalf Corvotempesta wrote:
i'm doing some maintenance replacing some not-yet-failed HDD with WD RED SSD.
I've read the warning on the homepage
https://raid.wiki.kernel.org/index.php/Linux_Raid
Are SSD drives still subject to SMR ? I've thought that it was related
only to magnetic drives not on SSD.
SMR is not applicable to flash-based storage. I expect the warning
on the wiki was written at a time when the only drives bearing the
WD Red brand were HDDs, not any SSDs.
Correct. Typically SATA SSDs do not expose SMR capabilities; it's all
hidden by the FTL there.
And the warning really is outdated. What matters is that the HDD needs
to support TLER (ie scterc capabilities); the brand or series really is
immaterial. There are plenty of non-SMR HDDs which do not support it.
Sadly it's not well advertised, so you really have to test
(or invest in the HDD range which is geared up for this kind of usage.)
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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